And for Windows too

src/Platform_Windows.c

@@ -1081,8 +1081,23 @@ cc_result Platform_Decrypt(const void* data, int len, cc_string* dst) {
 	return 0;
 }
 
+static BOOL (WINAPI *_RtlGenRandom)(PVOID data, ULONG len);
+
 cc_result Platform_GetEntropy(void* data, int len) {
-	return ERR_NOT_SUPPORTED;
+	static const struct DynamicLibSym funcs[] = {
+		DynamicLib_Sym2("SystemFunction036", RtlGenRandom)
+	};
+
+	if (!_RtlGenRandom) {
+		static const cc_string kernel32 = String_FromConst("ADVAPI32.DLL");
+		void* lib;
+		
+		DynamicLib_LoadAll(&kernel32, funcs, Array_Elems(funcs), &lib);
+		if (!_RtlGenRandom) return ERR_NOT_SUPPORTED;
+	}
+	
+	if (!_RtlGenRandom(data, len)) return GetLastError();
+	return 0;
 }
 
 

third_party/bearssl/src/config.h

@@ -42,6 +42,11 @@
 #undef _WIN32
 #endif
 
+/* Rely on ClassiCube's implementation for RNG */
+#define BR_USE_WIN32_RAND 0
+#define BR_USE_URANDOM 0
+#define BR_USE_GETENTROPY 0
+
 /*
  * When BR_64 is enabled, 64-bit integer types are assumed to be
  * efficient (i.e. the architecture has 64-bit registers and can

third_party/bearssl/src/ssl_engine.c

@@ -24,62 +24,6 @@
 
 #include "inner.h"
 
-#if 0
-/* obsolete */
-
-/*
- * If BR_USE_URANDOM is not defined, then try to autodetect its presence
- * through compiler macros.
- */
-#ifndef BR_USE_URANDOM
-
-/*
- * Macro values documented on:
- *    https://sourceforge.net/p/predef/wiki/OperatingSystems/
- *
- * Only the most common systems have been included here for now. This
- * should be enriched later on.
- */
-#if defined _AIX \
-	|| defined __ANDROID__ \
-	|| defined __FreeBSD__ \
-	|| defined __NetBSD__ \
-	|| defined __OpenBSD__ \
-	|| defined __DragonFly__ \
-	|| defined __linux__ \
-	|| (defined __sun && (defined __SVR4 || defined __svr4__)) \
-	|| (defined __APPLE__ && defined __MACH__)
-#define BR_USE_URANDOM   1
-#endif
-
-#endif
-
-/*
- * If BR_USE_WIN32_RAND is not defined, perform autodetection here.
- */
-#ifndef BR_USE_WIN32_RAND
-
-#if defined _WIN32 || defined _WIN64
-#define BR_USE_WIN32_RAND   1
-#endif
-
-#endif
-
-#if BR_USE_URANDOM
-#include <sys/types.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <errno.h>
-#endif
-
-#if BR_USE_WIN32_RAND
-#include <windows.h>
-#include <wincrypt.h>
-#pragma comment(lib, "advapi32")
-#endif
-
-#endif
-
 /* ==================================================================== */
 /*
  * This part of the file does the low-level record management.